If you are wondering why WW1 American soldiers were called “doughboys” here’s what wiki has to say about it:

The origins of the term are unclear. It was in use as early as the 1840s.[3][4An often cited explanation is that the term first came about during the Mexican–American War, after observers noticed U.S. infantry forces were constantly covered with chalky dust from marching through the dry terrain of northern Mexico, giving the men the appearance of unbaked dough.[5] Another suggestion also arises from the Mexican–American War, and the dust-covered infantry men resembled the commonly used mud bricks of the area known as adobes.[5] Another suggestion is that doughboys were so named because of their method of cooking field rations of the 1840s and 1850s, usually doughy flour and rice concoctions baked in the ashes of a camp fire, although this does not explain why only infantryman received the appellation.[5]

Slate.com offered this charming New Years greeting on Monday – a 95-year-old water colour painting of a holiday season snow ball fight between First World War doughboys. Painted on Dec. 28, 1917 on the first page of a letter home, the piece was the work of Pvt. Salvatore Cillis, a 25-year-old Italian-born American soldier attached to the U.S. Army’s 306th Field Artillery. At the time, the unit was stationed at Camp Upton on Long Island awating orders to head to France. A Manhattan sign painter in peacetime, the young artists sent a number of paintings and sketches to his family during his time in uniform. The works represent Cillis’ own light-hearted take on the war and army life. A collection of his work now belongs to the New York Historical Society Museum and Library. To read more about Cillis and to see his paintings and sketches, click here